Air Cleaners Optimization with CFD, Finite Element, and Thermal Analysis

Heating, ventilation, and air-conditioning – HVAC systems form an integral part of most working buildings, as well as a large proportion of homes. Ensuring that they are supplying not only suitable ambient temperatures but also air that is sufficiently clean and of good quality, is important to maintaining good health and a comfortable working and living environment.

Proper filtration is key to ensuring good quality air and a minimum level of air pollutants. When it comes to measuring the suitability of one type of air cleaner versus another, two factors are of critical importance – temperature and pressure drop through the air cleaner. These can both be affected by such factors as the cleanliness or dirtiness of the filters, their porosity, fiber diameter and thickness, woven versus non-woven, and whether they are pleated or straight.

Of course, when a new building is being erected, or the HVAC system in an existing building is being upgraded or replaced, it is beneficial to know which type of filtration system will best work for that building before investing a great deal of money on it. This is, of course, true in the case of car air filters as well.

This is where simulations come into play.

CFD to Optimize Air Filtration and Reduce Air Pollutants

Specific factors, as mentioned before, have a significant effect on the effectiveness of an HVAC’s air filtration system. Each of these factors (cleanliness, porosity, diameter, etc) has an effect on the fluid flow of the air through the air conditioning system (How to Design Better Air Conditioning Systems with Simulation), meaning that they need to be installed in such a way as to provide optimal flow.
CFD simulations rely on numerical and algorithmic analysis to inspect the issues that could arise due to restricted of inefficient airflows and provide suitable solutions to the problem.

The benefits of CFD are many (CFD in HVAC Systems Applications). The system doesn’t require a physical setup, as everything is done using specialized software. This software is powerful enough to mimic almost any physical phenomenon for which there is a mathematical model, and is capable of providing workable solutions after running a single engineering simulation. The system does require significant computing power, though, and is best interpreted by someone with an understanding of complex math, physics and computer science. SimScale is trying to tackle this issue by providing plenty of webinars and learning resources for free and optimizing the CAE software to be as user-friendly as possible. Furthermore, being cloud-based, users don’t have to worry about the computing power required, they only need a normal PC to perform simulations.

Air cleaners benefit especially from CFD because of the number of variables involved. For example, in the move towards greener buildings, optimizing airflow is critical to reducing energy waste and maximizing the use of natural flows to augment the system. With CFD it is possible to better plan the placement, materials and quantity of filters to ensure that not only is clean air being delivered, but its flow is not being hampered by inefficient air filtration.

With SimScale, you have the option to choose between laminar and turbulent models, based on the fluid flow Reynolds number, with solvers that support steady-state as well as transient setups and more.

Thermodynamic Simulation to Reduce Energy Consumption

Temperature has a significant effect on the efficiency of the filtration in any HVAC system. These systems are affected by heat transfer, mass flow, velocity, the relationship between the pressure, temperature, and matter state – gas or liquid – of the fluid within the system.

Quantity, dimensions, and layout of HVAC components, and, in particular, air filtration systems, is of great significance to ensure the system is working at its most efficient. Ensuring the optimal pressure, mass and flow direction can be successfully done with the right simulation.

With proper thermodynamic analysis, it is possible to not only understand the fluid flow but also to adjust them to reduce energy consumption, improve the positioning of machinery to optimize accuracy and precision, reduce noise emission and reduce the burden on machinery to ensure it lasts and works efficiently for longer.

In the case of air cleaners, thermodynamic simulations can help plan the positioning, type and quantity of filters to optimize heating and cooling while reducing energy costs. For example, when installing air cleaners into an office building, simulation can indicate the best placement for them to ensure the airflow is optimized to bring the work areas to optimum comfort levels while minimizing airborne particles and wear and tear on the filter, which in turn reduces the building’s energy requirements and costs.

A thermal analysis performed with SimScale can predict the behavior of your application or the structural response of a component based on thermal loads and can provide a deeper understanding of the heat flow through adjacent regions.

FEA for Predicting the Longevity of Air Cleaners and Parts

HVAC systems are, like everything else, composed of materials that have been processed and manufactured into the relevant components. Each of these materials has its own particular properties, including the air cleaners as mentioned above.

Using the actual data of the air cleaners – such as their composition, thickness, porosity, etc – FEA can, through a computerized CAD model, accurately predict the longevity of the product based on its reaction to real-world stressors, such as temperature fluctuations, pressure, fluid flow, vibration, and dirtiness.

Structural analysis of a rotor

FEA provides the user with accurate, safe renditions of the actual workings of the proposed system. Results are comprehensive and a single model can be used to generate data on a variety of potential failures. With this method, one can simultaneously calculate and visually represent numerous parameters, including those mentioned above.

Using FEA when planning an HVAC system can ensure that the optimal materials are used for the filtration system. For example, in a factory setting, it is vital to ensure adequate flow of clean, fresh air, while filtering harmful particles effectively. With FEA, it is possible to choose the best kind of filters to handle the particle load and estimate their useful life more accurately.

Therefore, structural mechanics simulations for air filtration can help you understand the physical behavior of your system, using either natively single parts or complete CAD assemblies.

Selecting the right type of simulation for your project depends on what exactly you need to achieve. Do you have a heavy, medium or light filtration requirement? Is the focus on ensuring the longevity of air filters? Do you need a holistic view of the system to help with planning? Speaking to a professional company that specializes in simulations will help you choose the right modeling option for your needs.

And if you want to read more about engineering simulation and real applications in air contamination cases, here are two blog posts worth reading:

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Md Asif Rahman

Post-graduate who is in love with CFD and Thermodynamics. Passionate about writing, traveling and geeky gadgets.